Maximum Parellelism in 2018.1.2 Significantly Slowing Deployments

We recently updated to 2018.1.2 from 3.17.13. Post-update, our Staging environment deploys seemed to be taking 25-40% longer. Our first Production deploy to 'A side' took 61 minutes (19:41 - 20:42). The two previous 'A side' deploys, using version 3.17.13 took 32 minutes (18:36-19:08) and 27 minutes (19:59-20:26). Looking back, all of our 'A side' deploys finished in 30-35 minutes, since we had made all steps run in parallel with the previous steps. We have 184 steps deploying to 78 targets (just for A side). Even though the UI would stutter during deploys with everything set to parallel, it was very quick. As I monitored the most recent deploy, I noticed that it was behaving as if we did not have parallelism enabled, or more precisely, that it was only running through 8-10 concurrent steps at a time (like a multi-car train going from step 1 to 184), and never jumping ahead to steps it previously jumped to under 3.17.13. I began researching and found the updated information linked below, describing how maximum parallelism is limited to 10 steps at a time. There is no information provided on how we can override this value, but we must be allowed to do so. Doubling our deployment time in order to have a more stable UI is a net loss for us. We deploy to 4 environments now, with 4 more online shortly, so it will significantly impact the workflow we established under version 3.17.13. Please let me know if/how maximum parallelism can be upped from default value of 10.

I appreciate the quick response. I added the setting to 'Project Variables', however, I have not seen an increase in parallel tasks. It still seems to be limited to the default '10' (see attached screenshot showing 10 active tasks). I've tried multiple values and have not seen a difference. Should I be placing this setting in our Library set and scoped to the environment?